It is known from the art to use child safety seats for a vehicle with a harness for restraining a passenger. The harness is to be tightened and clamped at a predetermined tension whereby the level of tension is determined by means of indicators, e.g. such as tension indicators as described in EP 1896302.
A child safety seat for a vehicle can only guarantee a maximum of safety if the person restrained in the seat is tightened by a harness under very specific conditions. Besides the location of the harness on the child's body the tension of the harness is of paramount importance. While it is obvious that a harness which is loose can not maintain its function to restrain a passenger, a harness that is tightened too much will be very uncomfortable for the passenger and hence not suitable for a longer journey.